Updated SPI pins so that they are configurable, enabling multiple SPI sercoms for ATSAMD21

src/machine/board_arduino_nano33.go

@@ -122,7 +122,12 @@ const (
 
 // SPI on the Arduino Nano 33.
 var (
-	SPI0 = SPI{Bus: sam.SERCOM1_SPI}
+	SPI0 = SPI{Bus: sam.SERCOM1_SPI,
+		SCK:   SPI0_SCK_PIN,
+		MOSI:  SPI0_MOSI_PIN,
+		MISO:  SPI0_MISO_PIN,
+		DOpad: spiTXPad2SCK3,
+		DIpad: sercomRXPad0}
 )
 
 // I2S pins

src/machine/board_circuitplay_express.go

@@ -111,7 +111,12 @@ const (
 
 // SPI on the Circuit Playground Express.
 var (
-	SPI0 = SPI{Bus: sam.SERCOM3_SPI}
+	SPI0 = SPI{Bus: sam.SERCOM3_SPI,
+		SCK:   SPI0_SCK_PIN,
+		MOSI:  SPI0_MOSI_PIN,
+		MISO:  SPI0_MISO_PIN,
+		DOpad: spiTXPad2SCK3,
+		DIpad: sercomRXPad0}
 )
 
 // I2S pins

src/machine/board_feather-m0.go

@@ -85,7 +85,12 @@ const (
 
 // SPI on the Feather M0.
 var (
-	SPI0 = SPI{Bus: sam.SERCOM4_SPI}
+	SPI0 = SPI{Bus: sam.SERCOM4_SPI,
+		SCK:   SPI0_SCK_PIN,
+		MOSI:  SPI0_MOSI_PIN,
+		MISO:  SPI0_MISO_PIN,
+		DOpad: spiTXPad2SCK3,
+		DIpad: sercomRXPad0}
 )
 
 // I2S pins

src/machine/board_itsybitsy-m0.go

@@ -2,7 +2,9 @@
 
 package machine
 
-import "device/sam"
+import (
+	"device/sam"
+)
 
 // GPIO Pins
 const (
@@ -85,7 +87,30 @@ const (
 
 // SPI on the ItsyBitsy M0.
 var (
-	SPI0 = SPI{Bus: sam.SERCOM4_SPI}
+	SPI0 = SPI{Bus: sam.SERCOM4_SPI,
+		SCK:   SPI0_SCK_PIN,
+		MOSI:  SPI0_MOSI_PIN,
+		MISO:  SPI0_MISO_PIN,
+		DOpad: spiTXPad2SCK3,
+		DIpad: sercomRXPad0}
+)
+
+// "Internal" SPI pins; SPI flash is attached to these on ItsyBitsy M0
+const (
+	SPI1_CS_PIN   = PA27
+	SPI1_SCK_PIN  = PB23
+	SPI1_MOSI_PIN = PB22
+	SPI1_MISO_PIN = PB03
+)
+
+// "Internal" SPI on Sercom 5
+var (
+	SPI1 = SPI{Bus: sam.SERCOM5_SPI,
+		SCK:   SPI1_SCK_PIN,
+		MOSI:  SPI1_MOSI_PIN,
+		MISO:  SPI1_MISO_PIN,
+		DOpad: spiTXPad2SCK3,
+		DIpad: sercomRXPad1}
 )
 
 // I2S pins

src/machine/board_trinket.go

@@ -62,7 +62,12 @@ const (
 
 // SPI on the Trinket M0.
 var (
-	SPI0 = SPI{Bus: sam.SERCOM0_SPI}
+	SPI0 = SPI{Bus: sam.SERCOM0_SPI,
+		SCK:   SPI0_SCK_PIN,
+		MOSI:  SPI0_MOSI_PIN,
+		MISO:  SPI0_MISO_PIN,
+		DOpad: spiTXPad2SCK3,
+		DIpad: sercomRXPad0}
 )
 
 // I2C pins

src/machine/machine_atsamd21.go

@@ -871,7 +871,12 @@ func waitForSync() {
 
 // SPI
 type SPI struct {
-	Bus *sam.SERCOM_SPI_Type
+	Bus   *sam.SERCOM_SPI_Type
+	SCK   Pin
+	MOSI  Pin
+	MISO  Pin
+	DOpad int
+	DIpad int
 }
 
 // SPIConfig is used to store config info for SPI.
@@ -886,12 +891,13 @@ type SPIConfig struct {
 
 // Configure is intended to setup the SPI interface.
 func (spi SPI) Configure(config SPIConfig) {
-	config.SCK = SPI0_SCK_PIN
-	config.MOSI = SPI0_MOSI_PIN
-	config.MISO = SPI0_MISO_PIN
 
-	doPad := spiTXPad2SCK3
-	diPad := sercomRXPad0
+	config.SCK = spi.SCK
+	config.MOSI = spi.MOSI
+	config.MISO = spi.MISO
+
+	doPad := spi.DOpad
+	diPad := spi.DIpad
 
 	// set default frequency
 	if config.Frequency == 0 {